Cubital Fossa Discussion

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  • Triangular Hollow
  • Situated in front of elbow
  • Medial border is formed by lateral border of Pronator Teres
  • Lateral border is by medial border of Brachioradialis
  • Apex- Meeting of brachioradialis and pronator teres
  • Base is directed upward and is formed by an imaginary line joining the lateral and medial epicondyle.
  • Roof is formed by from superficial to deep-
    • Skin
    • Superficial facia containing cephalic(laterally) and basilic vein(medially) and the median cubital vein connecting the two.
      • Cephalic Vein is accompanied by lateral cutaneous nerve of forearm
      • Basilic vein is accompanied by median cutaneous nerve of forearm
      • Median Cubital Vein Applied- Used for venepuncture, IV injections, because –
        • Most superficial vein hence easily accessed
        • Well supported by underlying bicipital aponeurosis
        • Well anchored to deep veins by a perforating vein hence does not slip during procedure
    • Deep Fascia
    • Bicipital aponeurosis
  • Floor is formed by-
    • Upper part is formed by brachialis
    • Lower part is formed by supinator
  • Contents from medial to lateral-
    • M- Median Nerve medially-
      • Root Value- C5-T1
      • Branch of lateral and medial cords of brachial plexus
      • Applied anatomy of injury to median nerve in this region- Can be injured in case of supracondylar fracture of humerus
    • B- Brachial artery: –
      • Continuation of: Axillary Artery
      • Extent: Begins at lower border of teres major muscle
      • Terminates: In front of elbow at the level of neck of radius.
      • Terminal branches: Superficial lateral radial artery and deep medial ulnar artery.
    • B- tendon of Biceps brachii-
      • Passes backwards and laterally to be attached on radial tuberosity.
    • S – Superficial Radial Nerve (Lateral most)- passes between the brachioradialis and brachialis.
      • Root value: C5- T1
      • Branch of posterior cord of brachial plexus
      • Divides into 2 terminal branches at the level of lateral epicondyle-
        • Sensory Superficial radial nerve- passes under brachioradialis
        • Motor Deep radial nerve/ Posterior Interosseus Nerve- disappears in substance of supinator.
      • Effect of injury of radial nerve in this region- Motor supply to deep extensors of forearm Is lost –
        • Supination of forearm by supinator
        • Abduction of thumb by abductor policis longus
        • Extension of thumb at MCP joint and extension at CMC joint by Extensor Policis brevis
        • Extension of thumb joints by Extensor policis longus
        • Extension of wrist and index finger by Extensor Indices
  • After giving off its muscular branches to the biceps brachii and brachialis muscles, Musculocutaneous nerve continues as the lateral cutaneous nerve of the forearm
  • Medial cutaneous nerve of forearm is a branch of Median Nerve, branch from medial cord of brachial plexus.
  • Formation and Termination of basilic vein? –
    • The basilic vein begins as the continuation of the medial end of the dorsal venous arch of the hand.
    • It runs upwards along the back of the medial border of the forearm, winds round this border near the elbow to reach the anterior aspect of the forearm, where it continues upwards in front of the elbow along the medial side of the biceps brachii up to the middle of the arm, where it pierces deep fascia, unites with the brachial veins and runs along the medial side of the brachial artery to become continuous with the axillary vein at the lower border of the teres major
    • Basilic vein is the postaxial vein of the upper limb and corresponds to the short saphenous vein of the lower limb.
  • Cephalic vein formation and Termination?-
    • The cephalic vein begins as the continuation of lateral end of the dorsal venous arch.
    • It crosses the roof of anatomical box, ascends on the radial border of the forearm, continues upwards in front of elbow along the lateral border of biceps, pierces the deep fascia at the lower border of the pectoralis major, runs in cleft between the deltoid and pectoralis major (deltopectoral groove) up to the infraclavicular fossa, where it pierces the clavipectoral fascia and drains into the axillary vein.
    • Cephalic vein is the preaxial vein of the upper limb and corresponds to the great saphenous vein of the lower limb.
  • Bicipital aponeurosis attaches to Deep fascia of medial aspect of forearm.
  • Unique feature of nerve supply of brachialis- Dual innervation-
    • Medial 2/3rd by musculocutaneous nerve
    • Lateral 1/3rd by radial nerve
  • Pronator Teres-
    • Origin:
      • Superficial humeral head from medial epicondyle of humerus
      • Deep ulnar head from medial margin of coronoid process of ulna
    • Insertion Rough impression on the middle one-third of the lateral surface (most convex part) of the radius
    • Nerve Supply Median Nerve
    • Action Main pronator of forearm, flexion of elbow
  • Brachioradialis-
    • Origin – Upper two-third of the lateral supracondylar ridge of the humerus
    • Insertion – Lateral surface of the distal end of radius just above the styloid process
    • Nerve Supply Radial nerve
    • Action –
      • Flexes the elbow joint.
      • Pronates the supinated forearm to midprone position.
      • Supinates the pronated forearm to midprone position